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Accelerated ageing of plants to shorten the post-entry quarantine testing period

Novel plant genetics are required by horticultural industries to keep up with changes in consumer demands and the changing climate.

 

For cherry (Prunus spp.) growers the importation of new material involves a lengthy post-entry quarantine (PEQ) period where the trees to go through two growth periods. Demand for PEQ facility space is high so new methods to speed up PEQ will be advantageous to both importers and regulators.

 

PEQ is required to keep unwanted pathogens out of New Zealand. The quarantine level and conditions are designed to maximise the likelihood of detection for target organisms.

 

The speed of plant growth and aging depends on the environment. For example, cherries can be produced in a very short season in Norway due to the mild temperatures and long day-lengths. Applying these conditions to PEQ could almost halve the time required to cycle through two growth cycles. However, it is unclear what impact this would have on the ability to detect pathogens.

 

This project compares current Ministry for Primary Industries (MPI) PEQ protocols with accelerated aging protocols using climate controlled Biotron facilities at Lincoln University.

 

The initial experiment will use cherry trees. Cherry tree growth will be measured and compared between the two conditions. Grafted budwood will be inoculated with Prunus necrotic ringspot virus, Pseudomonas syringae pv. syringae, and Monilinia fructicola.

 

Molecular diagnostic protocols will be used to test the ability to detect these pathogens. These pathogens were selected as they are found in New Zealand but are closely related to unwanted organisms on MPI’s Prunus Import Health Standard.

 

The outputs from this project aim to inform changes to MPI’s PEQ protocols and facilities.

 

Contact Project Leader Rebekah Frampton: rebekah.frampton@plantandfood.co.nz